Bridgeless AC-DC converters are known in the art. Conventional bridgeless circuits operating in the transition mode (TM) suffer from high switching losses and a very high common mode EMI. In addition they make poor utilization of their magnetic components and semiconductor devices. Totem-pole output bridgeless circuits, when operated in continuous conduction mode (CCM), have reduced common mode EMI but are only practical with GaN devices because of the slow reverse recovery of the body diode of silicon semiconductors. If these devices operate in the transition mode (TM) with what is known as “valley switching,” the reverse recovery problem is resolved but they may have significant switching losses at high input line. Both the CCM and TM totem-pole bridgeless circuits present current and voltage sensing challenges.
Thus, there is a need for a new bridge was AC-DC converter circuit having a totem-pole output operating in or near transition mode.